1. Field of the Invention
The present invention relates to a reflecting device, a communicating pipe, an exhausting pump, an exhaust system, a method for cleaning the system, a storage medium storing a program for implementing the method, a substrate processing apparatus, and a particle capturing component, and in particular relates to a reflecting device, a communicating pipe, an exhausting pump, an exhaust system and a method for cleaning the system and a storage medium that prevent infiltration of particles into a processing chamber of the substrate processing apparatus.
2. Description of the Related Art
Generally, a substrate processing apparatus that carries out predetermined processing on substrates such as semiconductor device wafers has a processing chamber (hereinafter referred to as “chamber”) in which a substrate is housed and subjected to the predetermined processing. In such a chamber, particles resulting from adherents to a chamber inner wall and reaction products generated by the predetermined processing are suspended. When these suspended particles adhere to the substrate surface, in a produce manufactured from the substrate, for example, in a semiconductor device, short-circuit in wiring occurs, and yield of the semiconductor device reduces. Therefore, in order to remove the particles in the chamber, the substrate processing apparatus exhausts a gas in the chamber by an exhaust system.
The exhaust system of the substrate processing apparatus has a turbo molecular pump (Turbo Molecular Pump) (hereinafter, referred to as “TMP”) that is an exhausting pump capable of achieving high vacuum, and a communicating pipe that allows the TMP and an inside of the chamber to communicate with each other. The TMP has a rotary shaft disposed along an exhaust stream, and a plurality of blade-shaped rotary blades which are orthogonally projected from the rotary shaft, and the rotary blades rotate at a high speed around the rotary shaft at a center, whereby the TMP exhausts a gas upstream of the rotary blades towards downstream of the rotary blades at a high speed. The exhaust system discharges the particles, in the chamber as well as the gas in the chamber by operating the TMP.
However, in recent years, it has been found out that particles flow back into the chamber from the exhaust systems. Specifically, it has been found out that the adherents which adhere to the rotary blades of the TMP peel off and flow back into the chamber, or the particles discharged from the chamber collide against the rotary blades of the TMP and rebound, and directly flow back into the chamber.
It is considered that the adherents which peel off from the rotary blades, and the particles which rebound by the rotary blades are both given large kinetic energy from the rotary blades which rotate at a high speed, and therefore, they repeat elastic collisions with the inner wall of the communicating pipe, and infiltrate the chamber in spite of the presence of the exhaust stream in the communicating pipe.
Concerning the above described backflow of the particles, the adherents which peel off from the rotary blades are prevented from generating by increasing the replacement frequency of the TMP (for example, refer to, “Visualization of Backflow Particles from Turbo Molecular Pump”, Sato et al., Japan Industrial Publishing Co., LTD, Clean Technology, 2003.6, pages 20 to 23).
However, collision between the particles and the rotary blades occurs accidentally, and therefore, particles rebounded by the rotary blades cannot be prevented from occurring even if replacement frequency of the TMP is increased. The rebounded particles repeat elastic collisions with the inner wall of the communicating pipe and infiltrate the chamber as described above, and adhere to substrate surfaces, which reduces yields of the products manufactured from the substrates.
The adherents to the chamber inner wall and adherents to the components in the chamber peel off due to vibration of the chamber, a viscous force of the gas flowing in the chamber, electromagnetic stress caused by an electric field in the chamber, or the like, and therefore, the timing at which these adherents peel off to be particles is unpredictable. On the other hand, exhaust in the chamber by the exhaust system is performed at a predetermined timing, and therefore, if the timing at which the adherent peel off and the timing at which exhaust in the chamber is are carried out are different, the particles are not removed from the chamber.
There is known a method for capturing some particles in the chamber which are negatively charged by plasma by electrodes disposed in the camber, but in this method, the particles which are not charged cannot be captured. In order to dispose the electrodes in the chamber, the construction of the chamber needs to be changed significantly, and therefore, it is difficult to dispose the electrodes in the chamber.